This invention relates to an electronic tone generation apparatus, such as for use in an electronic musical instrument, in which external acoustic signals are recorded in a digital form, modified, and sounded as a modified sound.
Heretofore, it has been in practice to store externally applied acoustic signals of musical sounds of musical instruments such as piano, violin, etc. or voices of birds in a memory in a digital form through a proper modulation system, e.g., PCM (pulse coded modulation) and read out the stored signals from the memory as tone signals of a keyboard musical instrument.
Copending U.S. patent applications Ser. Nos. 760,290 and 760,291 both filed Jul. 29, 1985 and assigned to the same assignee as this application disclose a musical instrument of such a type as described above. The '290 application issued as U.S. Pat. No. 4,681,008 on Jul. 21, 1987 and the '291 application issued as U.S. Pat. No. 4,667,556 on May 26, 1987.
This type of keyboard musical instrument or apparatus, which is called sampling machine, because of a sampling function, may be designed to have an over-dubbing function, i.e., a function of superimposing a plurality of previously recorded acoustic signals to produce a separate tone signal. None of such apparatuses with overdubbing function, however, has yet been put into practice.